Bar Harbor Systemwide Conveyance Assessment: How Smart Controls Helped the Town Develop a Cost-Effective Solution to Meet CSO Mitigation Requirements

Bar Harbor Systemwide Conveyance Assessment: How Smart Controls Helped the Town Develop a Cost-Effective Solution to Meet CSO Mitigation RequirementsAbstractIntroduction: The Town of Bar Harbor, ME (the Town), a popular tourist destination due to its proximity to Acadia National Park, operates four CSOs that discharge to Frenchman's Bay where water recreation is highly valued. The Town has two wastewater treatment facilities (WWTF); included in NPDES permits for the WWTFs are requirements for development, and periodic updates, of a CSO Master Plan to abate CSOs from the Town's four CSO outfalls. Bar Harbor prepared its first CSO Master Plan in 2006, the most recent update to the plan was approved by the Maine Department of the Environment (MEDEP) in 2021. The purpose of the CSO Master Plan is to identify abatement projects and intended implementation schedule to better control and reduce CSOs and to report on progress towards achieving those results. Project Overview: A systemwide conveyance assessment was conducted to evaluate the potential hydraulic performance for infrastructure improvements and infiltration/inflow (I however, prior to the model development, the Town had no way to quantify the potential improvement from these projects. The alternatives were combined in several different combinations to determine the most effective scenarios to achieve the assessment goals. The five most effective scenarios with respect to feasibility and performance were identified and modeled. Each scenario was evaluated with implementing three levels of I the tank was not originally utilized for lower volume storm events and thus the project not maximizing the benefits from the Town's infrastructure investment. By modeling the system using smart, real-time controls, the evaluation showed that the storage tank should be utilized for storage during smaller events, without compromising its goal eliminate CSOs from the West Street CSO Outfall during the 5-year event. The evaluation showed that with these two infrastructure improvement projects, combined with implementation of a 25% I&I reduction program, the Town would not need to complete other CIP projects originally thought to be necessary to meet assessment goals — saving the Town millions of dollars in unnecessary infrastructure improvements. Conclusion: The systemwide conveyance assessment of the collection system is complete and the Town has a plan to achieve CSO mitigation regulatory requirements, as stated in their CSO Master Plan. The West Street PS and CSO Storage Tank Project design is nearing completion and is planned to go out to bid in spring 2024 with construction starting in early summer 2024. With this assessment complete, the Town has the data and information necessary to justify to their ratepayers the benefits and necessity of the ongoing system improvements and planned capital investments into the collection system. The Town also has the data and information necessary to justify the effectiveness of the planned capital improvements to the MEDEP and the information to support completion of the next CSO Master Plan Update which is required to be submitted to ME DEP by March 28, 2027. With the collection system upgrades planned, once constructed, the Town will also have the real-time data needed to verify system improvements are meeting their CSO mitigation goals and the ability to adapt system logic, if necessary, to improve system performance. A truly adaptive solution.This paper was presented at the WEF Collection Systems and Stormwater Conference, April 9-12, 2024.SpeakerBraga, AndreaPresentation time13:30:0014:00:00Session time13:30:0016:45:00SessionCombined Sewer OverflowSession number07Session locationConnecticut Convention Center, Hartford, ConnecticutTopicCollaboration, Combined Sewer Overflow, Combined Sewer System, Construction, Deep Sewer Tunnel, Flow control, Long Term Control Planning, Modeling, Predictive Analytics, Public Education/Information/Communication, Pump station, forcemain, Regulatory Compliance - Collection Systems, Sewer Separation, Wet WeatherTopicCollaboration, Combined Sewer Overflow, Combined Sewer System, Construction, Deep Sewer Tunnel, Flow control, Long Term Control Planning, Modeling, Predictive Analytics, Public Education/Information/Communication, Pump station, forcemain, Regulatory Compliance - Collection Systems, Sewer Separation, Wet WeatherAuthor(s)Braga, AndreaAuthor(s)A. Braga1, M. Dever1, B. LeavittAuthor affiliation(s)Jacobs 1SourceProceedings of the Water Environment FederationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Apr 2024DOI10.2175/193864718825159383Volume / Issue Content sourceCollection Systems and Stormwater ConferenceCopyright2024Word count21